Thermosetting polyester composition containing normally solid carboxy-containing diene polymer

ABSTRACT

A thermosettable composition suitable for preparing reinforced plastic articles is prepared by combining an unsaturated polyester, a normally solid carboxy-containing polymer of a conjugated diene, a vinyl monomer, a catalyst and a reinforcing agent or filler. Preferably the composition is prepared utilizing a mixer giving moderate shear such as a twin-rotor mixer. The resulting composition when cured exhibits high impact strength and good surface finish.

BACKGROUND OF THE INVENTION

This invention relates to unsaturated polyester compositions containinga polymer of a conjugated diene.

It is known in the art to produce unsaturated polyester compositionscontaining rubber. However, it has been found that such compositionstend to exhibit separation when combined with a reinforcing agent orfiller, thus impairing the physical properties, particularly impactstrength.

Liquid or semi-solid rubbers which can simply be mixed with polyestersto produce thermosetting compositions are also well known and a broadspectrum of low molecular weight liquid or semi-solid rubbers aresuggested in the art for use in such compositions. However, lowmolecular weight rubber compositions tend to give very poor surfacefinish in systems containing a reinforcing agent or filler.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a thermosetting polyestercomposition having good impact strength and good surfacecharacteristics;

It is a further object of this invention to provide a molded articlehaving improved pigmentability.

It is still a further object of this invention to provide a curedthermoset article; and it is yet a further object of this invention toprovide a method for producing a polyester composition containing anormally solid polymer of a conjugated diene capable of giving highstrength articles having good surface characteristics.

In accordance with this invention there is provided a compositioncomprising an unsaturated polyester and a normally solidcarboxy-containing polymer of a conjugated diene in a composition alsocontaining a vinyl monomer, a catalyst and a reinforcing agent orfiller.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention concerns thermosetting composition comprising anunsaturated polyester, a normally solid carboxy-containing a polymer ofa conjugated diene, a vinyl monomer, a catalyst and one or morereinforcing agents or fillers.

The unsaturated polyesters are prepared by reacting an unsaturateddicarboxylic acid having 4 to 12 carbon atoms such as maleic, fumaric,itaconic, citraconic, mesaconic (or anhydrides or acid halides thereof),cis-2-dodecenedioc acid and mixtures thereof with one or more polyols.Representative polyols that can be used include alkylene glycols having2-10 carbon atoms, dialkylene glycols having 4-18 carbon atoms,glycerol, pentaerythritol, trimethylolpropane, trimethylpentanediol,trimethylpropanediol and hydrogenated bisphenol-A.

Up to one-half or more on a molar ratio of the unsaturated acid can bereplaced by one or more saturated polycarboxylic acids having from 2-12carbon atoms to modify the degree of unsaturation and reactivity of thepolyester. Illustrative of these are oxalic acid, malonic acid, succinicacid, methylsuccinic acid, glutaric acid, adipic acid, suberic acid,sebacic acid, the phthalic acids, naphthalene dicarboxylic acid,cyclohexane dicarboxylic acid, citric acid and the like and mixturesthereof.

The proportion of polyhydric alcohols having more than two hydroxygroups such as glycerol, pentaerythritol, etc. and the proportion ofpolycarboxylic acids having more than two carboxy groups such as citricacid is preferably less than about 5 mole percent each based on totalamount of polyol and polycarboxylic acid respectively so that apolyester is obtained with maximum esterification of the hydroxy andcarboxy groups without being so viscous that difficulty would beexperienced during subsequent compounding.

The carboxy-containing solid polymers of conjugated dienes of thisinvention are known polymers. Carboxy terminated polymers, for example,are described in U.S. Pat. Nos. 3,135,716 (Uraneck et al, June 1964) and3,242,129 (Wilder, March 1966), the disclosures of which are herebyincorporated by reference. The resulting polymers generally have acarboxyl content in the range of about 0.01 to 5 weight percent. Thepolymers of conjugated dienes for use in this invention are normallysolid and generally have a weight average molecular weight of 30,000 to400,000 or higher, preferably 50,000 to 250,000. In terms of inherentviscosity, the ranges encompassed are from about 0.4 to 3, morepreferably from about 0.6 to 2. Inherent viscosity is determined using0.1 gram per 100 ml of toluene at 25° C.

The diene addition in the polymers of conjugated dienes can be in the 1,2 mode or the 1, 4 mode or combinations thereof. The unsaturationmicrostructure of the polymers is generally in the range of from about 5to 76 percent vinyl, from about 5 to 60 percent trans and from about 15to 50 percent cis unsaturation.

The polymers of this invention include the homopolymers and copolymersof the conjugated dienes. Also included are copolymers of the conjugateddienes and a monovinyl-substituted aromatic hydrocarbon containing fromabout 8-18 carbon atoms per molecule. Examples of themonovinyl-substituted aromatic monomer include: styrene,3-methylstyrene, 4-n-propylstyrene, 4-cyclohexylstyrene,4-docecylstyrene .[..]. .Iadd.dodecylstyrene 2-ethyl-4-benzylstyrene,4-(4-phenyl-n-butyl)sytrene, 1-vinylnaphthalene, 2-vinylnaphthalene,t-butylstyrene and the like. The monovinyl-substituted aromatichydrocarbon can contain alkyl, cycloalkyl, and aryl substituents, andcombinations thereof such as alkylaryl in which the total number ofcarbon atoms in the combined substituents is generally not greater than12. Styrene is presently preferred because of its availability andeffectiveness. The polymerized conjugated diene content of these.[.copolymers.]. .Iadd.polymers .Iaddend.ranges from about 20 to 100weight percent, more preferably from about 55 to 100 weight percent.

Although the presently preferred conjugated diene is 1,3-butadiene, itis within the scope of the carboxy-containing polymers of this inventionto use conjugated dienes containing from 4-12 carbon atoms per molecule,more preferably from 4-8 carbon atoms per molecule. Examples of suchcompounds include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene,piperylene, 3-butyl-1,3-octadiene, 1-phenyl-1,3-butadiene, and the likeand mixtures thereof.

The conjugated diene-monovinyl-substituted aromatic hydrocarboncopolymers can be of random or block configuration or combinationsthereof. Block polymers are presently preferred.

The polymers of conjugated dienes of this invention can be preparedaccording to previously cited patents and by free radical polymerizationin solution, suspension or emulsion processes. For example,polymerization can be initiated with carboxy-containing compounds suchas azobis-cyanopentanoic acid, di(β-carboxypropionyl)peroxide (succinicacid peroxide) and the like. Chain transfer agents such as thioglycolicacid and the like are used to regulate the molecular weight of thepolymer produced in such processes.

It is within the scope of preparing the carboxy-containing polymers ofconjugated dienes to react polymers such as hydroxy terminated polymerswith an anhydride of an unsaturated dicaboxylic acid such as maleicanhydride, citraconic anhydride, .[..]. .Iadd.anhydride.Iaddend.itaconic anhydride, chloromaleic anhydride and the like toproduce polymers with attached groups terminated with a carboxy group.Other carboxy containing diene polymers can be prepared in emulsionsystems incorporating reactive unsaturated carboxylic acid monomers.

Also diene polymers can be modified with peroxide and unsaturatedreactive carboxylic acids or thio .[.containing .]. .Iadd.containing.Iaddend.carboxylic acids to give carboxy containing polymers.

The ratio of unsaturated polyester to carboxy-containing polymer of aconjugated diene generally ranges from about 15:1 to 0.5:1, preferablyfrom about 5:1 to 1:1.

Representative vinyl monomers include styrene, vinyltoluene,divinylbenzene, 2-vinylpyridine, diallyl phthalate, triallylisocyanurate, α-methylstyrene, alkyl acrylates and alkyl methacrylatesin which the carbon atoms in the alkyl groups range from 1 to about 6and the like and mixtures thereof. The presently preferred vinyl monomeris styrene because of its availability, reactivity, cost and desirableproperties. Total vinyl monomer from all sources is 15 to 300,preferably 30 to 200 parts by weight vinyl monomer per 100 parts byweight polyester plus polymer of a conjugated diene.

The catalysts used in this invention are conventional free radicalpolymerization initiators selected from among organic peroxides andhydroperoxides such as benzoyl peroxide, dicumyl peroxide, methyl ethylketone peroxide, lauryl peroxide, cyclohexanone peroxide, t-butylperbenzoate, t-butyl hydroperoxide, t-butylbenzene hydroperoxide, cumenehydroperoxide, t-butyl peroctoate and the like. In addition, azocompounds such as azobis-isobutyronitrile can be employed. A presentlypreferred catalyst is t-butyl perbenzoate. The catalyst is generallyused in the range from about 0.1 to 10 parts by weight per 100 parts byweight polyester plus carboxy-containing polymer of a conjugated diene,more preferably from about 1-5 parts by weight catalyst.

The reinforcing agents used in this invention comprise fibers selectedfrom among glass, asbestos, carbon, graphite, metal, synthetic polymerssuch as polyamides, polyester, polyolefins and the like and naturalfibers such as cotton, jute, hemp, sisal, flax, wood, paper and thelike. A presently preferred fiber is glass. The fibers can be used inthe form of mats, fabrics, threads, chopped fiber and the like. Thequantity of reinforcing agent is generally used in the range from about20 to 300 parts by weight per 100 parts by weight polyester pluscarboxy-containing polymer of a conjugated diene, more preferably fromabout 40 to 200 parts by weight reinforcing agent.

Desirably, from about 0.2 to 20 parts by weight, preferably from about 1to 10 parts by weight per 100 parts by weight of polyester pluscarboxy-containing polymer of a conjugated diene of an oxide orhydroxide of a Group II metal are added to the compositions of thisinvention. Exemplary of such compounds are the oxides and hydroxides ofmagnesium, calcium, strontium, barium and zinc. The compounds provide athickening function.

In addition to the previously named components of the compositions ofthis invention other optional additives can be used. These includefillers, pigments, colorants, lubricants, stabilizers, silane couplingagents and the like. Fillers include calcium carbonate, calciumsilicate, talc, clay, alumina, aluminum hydroxide, antimony trioxide,silica, mica, barium sulfate, calcium sulfate, and the like and mixturesthereof. Presently preferred fillers include calcium carbonate, clay andtalc because of availability and cost. The quantity of filler, whenused, is generally used in the range of from about 50 to 1000 parts byweight per 100 parts by weight polyester plus carboxy-containing polymerof a conjugated diene, more preferably from about 200 to 800 parts byweight filler.

A lubricant such as aluminum, barium, calcium, magnesium or zincstearate and the like in the range of from about 0.2 to 20 parts byweight, more preferably from about 1 to 15 parts by weight per 100 partsby weight carboxy-containing polymer of a conjugated diene pluspolyester can be used to impart mold release properties to thecompositions.

A stabilizer such as a barium or cadmium soap, a tin compound such astin octanoate, a phosphite such as dimethyl phosphite,tris(nonylphenyl)phosphite, alkyl phenols such as BHT, quinones, amines,and the like can be employed in an amount ranging from about 0.02 to 5parts by weight per 100 parts by weight polyester pluscarboxy-containing polymer of a conjugated diene.

Conventional colorants and pigments such as TiO₂, carbon black,phthalocyanine pigments and the like, and mixtures thereof, are employedas desired in amounts sufficient to give the desired color to the finalmolded product. The compositions of this invention possess outstandingpigmentability and smoothness. The ingredients are incorporated by amilling technique which involves moderate shear. This can beaccomplished by means of twin-rotor mixtures designed to give moderateshear to the paste-like ingredients. It is essential to provide someshear and because of the viscosity of the materials being mixed, propermixing cannot be obtained simply by stirring or by using a conventionalimpeller mixer. On the other hand, high intensity mixing which wouldgenerate excessive heat and activate the catalyst must be avoided also.Sheet molding compounding line mixing equipment can also be used. Thismixing under sufficient shear to achieve good dispersion of theingredients without heat buildup sufficient to activate the catalystinsures a good blend and is necessitated by the fact that the polymer ofthe conjugated diene is a normally solid material as opposed to a liquidor semi-solid. Shear which gives a heat build-up of 1-50, preferably2°-30° C. is satisfactory.

The curing can be done at a temperature known in the art for theparticular catalyst utilized. Generally a temperature of 100° to 200° C.and a time of 1 to 15 minutes in a press is sufficient.

EXAMPLE

Thermosetting compositions were prepared using a variety of butadienerubbers, some being carboxy-terminated and a commercially availableunsaturated polyester resin (3702-5, Koppers Co.). The polyester wasessentially a 0.9:1 mole ratio fumaric acid/propylene glycol resin withsome maleic acid units as indicated by nuclear magnetic resonanceanalysis.

Each composition was prepared by mixing a solution of the rubberdissolved in styrene with about 1/4 of the calcium carbonate filler in aBaker-Perkins sigma mixer for 5 minutes. The remaining calcium carbonatewas then added and mixed an additional 5 minutes. A mixture of thepolyester resin dissolved in styrene, magnesium hydroxide thickener,zinc stearate mold release agent and t-butyl perbenzoate catalyst whichhad been premixed was then added and mixed for 15 minutes. The choppedfiber glass reinforcing agent was added in 2 increments to the mixtureand mixing was continued an additional 10 minutes. Plaques, measuring 6inches ×6 inches×0.15 inches (15.2×15.2×0.38 cm), were compressionmolded from each composition for 5 minutes at 300° F. (149° C.) and7,000 psig (48.3 MPa gage). Each plaque was then evaluated to determineits physical properties. The nature and quantity of each component usedand physical properties determined are presented in Tables I and II.Microstructure of the polymers of conjugated dienes in Table I wasnormalized in consideration of styrene content. All of the ingredientsin Table II are in parts by weight.

The physical properties were determined in accordance with the testprocedures as follows:

Flexural modulus and flexural strength, ASTM D790.

Tensile and elongation, ASTM D256.

Shrinkage, ASTM D955.

Gloss, ASTM D523.

Average roughness, height in microns, was measured by a BendixProfilometer, Type QBA, LX-6 tracer, FT Skidmount.

Reverse impact, height in inches, was determined by dropping a 0.6 lb.(277 g) dart with rounded tip on a plaque. Failure is indicated ininches at which a crack or cracks appear on the reverse side.

Carboxy content was determined by calculation based on the molecularweight and amount of CO₂ coupling agent used. The carboxy content ofpolymer G was also determined by titration with sodium methoxide usingthymol blue indicator and the results correlated well with thecalculated value.

Molecular weight was determined by .[.gas.]. .Iadd.gel.Iaddend.permeation chromotography using THF as the solvent.

                  TABLE 1                                                         ______________________________________                                        Polymer of Conjugated Diene Characteristics                                            Micro-                                                                        struc-                                                                        ture % Buta-            Molecular                                             Vinyl/ diene             Weight                                             Wt. %   Trans/   Sty-  Inherent                                                                             Wt.   No.                                Polymer                                                                              CO.sub.2 H                                                                            Cis      rene  Viscosity                                                                            Avg.  Avg.                               ______________________________________                                        A.sup.(a)                                                                            0        9/53/38 75/25 0.95    83,000                                                                              68,000                            B.sup.(b)                                                                            0       11/55/34 52/48 1.12   101,000                                                                              57,000                            C.sup.(c)                                                                            0       10/45/45 60/40 0.77   160,000                                                                             120,000                            D.sup.(d)                                                                            0       --       70/30 1.12   128,000                                                                             113,000                            E.sup.(e)                                                                            0.035   --       70/30 1.21   154,000                                                                             125,000                            F.sup.(f)                                                                            0       --       70/30 1.77   256,000                                                                             209,000                            G.sup.(g)                                                                            0.26    61/17/22 100/0 0.36    23,800                                                                              18,100                            H.sup.(h)                                                                            0.02    11/47/42 71/29 1.52   177,000                                                                             119,000                            I.sup.(i)                                                                            0.025   75/8/17  71/29 1.11   172,000                                                                             130,000                            J.sup.(j)                                                                            --      --       --    --     --    --                                 ______________________________________                                         .sup.(a) Solprene 1205 block copolymer.                                       .sup.(b) Solprene 410 block copolymer.                                        .sup.(c) Solprene 414 radial block copolymer.                                 .sup.(d) Linear styrenebutadiene block copolymer.                             .sup.(e) Butadienestyrene carboxyterminated block copolymer containing        less than 10% styrenebutadiene X butadienestyrene linear block copolymer      where X is a coupling agent, the coupled polymer being produced as the        carboxyterminated polymer is formed.                                          .sup.(f) Linear styrenebutadiene-styrene block copolymer.                     .sup.(g) CO.sub.2 H terminated polybutadiene.                                 .sup.(h) A mixture of polymers consisting of about 48 wt. %                   styrenebutadiene block polymer of about a wt. average molecular weight of     100,000 containing the CO.sub.2 H end groups, about 46 wt. %                  styrenebutadiene X butadienestyrene linear block copolymer of about           200,000 wt. average molecular weight and about 6 wt. % polystyrene of         about 6,000 wt. average molecular weight (CO.sub.2 H terminated).             .sup.(i) Block copolymer, CO.sub.2 H terminated, 30% coupled similar to       polymer H.                                                                    .sup.(j) Commercially available polyvinyl acetate based product for use i     polyester formulations from Union Carbide.                               

                                      TABLE II                                    __________________________________________________________________________    Run Number        1    2    3    4    5    6    7    8    9                   __________________________________________________________________________    Polymer J         0    0    16   0    0    0    0    0    0                   Polymer A         0    0    0    26   0    0    0    0    0                   Polymer B         0    0    0    0    25   25   26   0    0                   Polymer C         0    0    0    0    0    0    0    25   0                   Polymer D         0    0    0    0    0    0    0    0    26                  Polymer E (0.035% COOH)                                                                         0    0    0    0    0    0    0    0    0                   Polymer F         0    0    0    0    0    0    0    0    0                   Polymer G (0.26% COOH)                                                                          0    0    0    0    0    0    0    0    0                   Polymer H (0.02% COOH)                                                                          0    0    0    0    0    0    0    0    0                   Polymer I (0.025% COOH)                                                                         0    0    0    0    0    0    0    0    0                   Styrene monomer   34   34   40   51   53   53   51   56   75                  Polyester resin   66   66   40   49   50   50   49   50   49                  Calcium carbonate 300  300  300  370  376  376  370  376  368                 Zinc stearate     3.5  3.5  3.5  4.3  4.4  4.4  4.3  4.4  4.3                 Magnesium hydroxide                                                                             1.9  1.9  1.9  2.4  0    0    2.4  2.4  2.4                 t-butyl perbenzoate                                                                             0.94 0.95 0.94 1.2  1.2  1.2  1.2  1.2  1.2                 1/4" glass fiber  71   71   70   87   125  125  87   88   86                  Days molded after compounding                                                                   5    0    0    0    0    4    7    0    7                   Flexural modulus, psi × 10                                                                2,220                                                                              2,080                                                                              1,860                                                                              1,640                                                                              1,740                                                                              1,720                                                                              nd   1,720                                                                              1,310               Flexural strength, psi                                                                          15,700                                                                             13,800                                                                             10,500                                                                             12,200                                                                             10,600                                                                             10,300                                                                             nd   11,300                                                                             10,800              Tensile break psi 4,230                                                                              3,980                                                                              4,720                                                                              5,020                                                                              .[.75,790.].                                                                       3,490                                                                              nd   6,660                                                                              4,130                                                     .Iadd.5590.Iaddend.                     Elongation, %     1    2    2    2    3    2    nd   3    2                   Notched Izod impact, ft. lbs/in.                                                                3.5  2.3  2.4  2.9  0.95 1.0  nd   2.6  2.4                 Unnotched Izod impact, ft. lbs/in.                                                              4.4  4.1  4.4  4.0  1.9  2.8  nd   3.4  4.4                 Reverse impact, inches (0.6 lb. dart)                                                           4    <3   3-6.sup.(a)                                                                        <3   nd   nd   6    <3   3.5                 Shore D Hardness  92   95   90   90   nd   nd   nd   90   90                  Average roughness, microns                                                                      0.22 0.46 0.45 0.74 0.40 0.55 nd   1.1  0.45                Shrinkage, mil/inch                                                                             3    3    -0.2 0    -0.8 -0.3 nd   -0.1 0.3                 Gloss, % at 60° angle                                                                    nd   60   28   nd   nd   nd   nd   19   19                  Density, g/cc     nd   2.1  2.0  2.0  nd   nd   nd   1.9  nd                  Remarks           Control                                                                            Control                                                                            Control                                                                            Control                                                                            Control                                                                            Control                                                                            Control                                                                            Control                                                                            Control             __________________________________________________________________________    Run Number        10   11   12   13   14   15   16   17   18                  __________________________________________________________________________    Polymer J         0    0    0    0    0    0    0    0    0                   Polymer A         0    0    0    0    0    0    0    0    0                   Polymer B         0    0    0    0    0    13   0    0    0                   Polymer C         0    0    0    0    0    0    0    0    0                   Polymer D         0    0    13   0    0    0    0    0    0                   Polymer E (0.035% COOH)                                                                         26   0    0    13   0    0    0    0    0                   Polymer F         0    26   13   13   0    0    0    0    0                   Polymer G (0.26% COOH-Low                                                                       0    0    0    0    25   13   0    0    0                   MW)                                                                           Polymer H (0.02% COOH)                                                                          0    0    0    0    0    0    25   25   0                   Polymer I (0.025% COOH)                                                                         0    0    0    0    0    0    0    0    25                  Styrene monomer   75   75   75   75   57   75   73   78   56                  Polyester resin   49   49   49   49   50   49   50   50   50                  Calcium carbonate 368  368  368  368  374  368  282  376  376                 Zinc stearate     4.3  4.3  4.3  4.3  4.4  4.3  4.5  4.4  4.5                 Magnesium hydroxide                                                                             2.4  2.4  2.4  2.4  2.4  2.4  2.4  2.4  2.4                 t-butyl perbenzoate                                                                             1.2  1.2  1.2  1.2  1.2  1.2  1.3  1.2  1.2                 1/4" glass fiber  86   86   86   86   88   86   88   88   88                  Days molded after compounding                                                                   7    7    7    7    6    7    6    0    0                   Flexural modulus, psi × 10                                                                1,070                                                                              1,150                                                                              1,190                                                                              1,080                                                                              1,420                                                                              1,230                                                                              1,030                                                                              1,230                                                                              1,640               Flexural strength, psi                                                                          13,100                                                                             9,980                                                                              11,200                                                                             11,800                                                                             13,400                                                                             12,900                                                                             12,500                                                                             14,500                                                                             11,300              Tensile break psi 7,280                                                                              4,270                                                                              5,570                                                                              6,000                                                                              3,830                                                                              4,890                                                                              8,090                                                                              6,710                                                                              5,300               Elongation, %     4    2    3    3    2    3    4    3    3                   Notched Izod impact, ft. lbs/in.                                                                2.6  2.9  3.6  3.6  3.4  3.3  2.5  2.6  4.4                 Unnotched Izod impact, ft. lbs/in.                                                              4.1  4.1  6.5  5.2  4.5  4.9  3.9  4.5  6.6                 Reverse impact, inches (0.6 lb. dart)                                                           14   8    5    10   11   10   7    12   6-12.sup.(b)        Shore D Hardness  88   90   90   89   nd   90   nd   90   90                  Average roughness, microns                                                                      0.25 0.35 0.35 0.28 1.9  1.5  0.32 0.42 0.43                Shrinkage, mil/inch                                                                             0.2  0.2  0.4  0.4  -0.2 -0.4 -0.1 -0.1 0                   Gloss, % at 60° angle                                                                    56   30   24   45   nd   23   nd   82   78                  Density, g/cc     nd   nd   nd   nd   nd   nd   nd   1.9  2.0                 Remarks           Invention                                                                          Control                                                                            Control                                                                            Invention                                                                          Control                                                                            Control                                                                            Invention                                                                          Invention                                                                          Invention           __________________________________________________________________________     .sup.(a) Broke at 6 inches, did not break at 3. Rerun showed actual value     to be 4 after 6 days aging.                                                   .sup.(b) Broke at 12, did not break at 6. Rerun showed actual value to be     9 after 4 days aging.                                                    

Inspection of the data presented in Table II shows that polyestercompositions in the absence of a polymeric modifier as in control runs 1and 2 yield relatively hard, brittle molded plaques with poor reverseimpact values of about 4 inches. The composition of control run 1 wasallowed to mature 5 days at room temperature before molding. Experiencehas shown such a maturation period is desirable to obtain the maximumphysical properties and this feature is observed in the poorerproperties shown in run 2. Control run 3 shows that LP-40A (a commercialpolyvinyl acetate product) included in the composition gives a moldedproduct having a reverse impact value of up to about 6 inches. However,compared with run 2, gloss is impaired and flexural strength is somewhatdecreased. The effect of adding various butadiene-styrene copolymers isshown in control runs 4-9. The results obtained are about the same asthose obtained in control run 3. The increase in reverse impact strengthwith the addition of carboxy-terminated normally solid polymers ofconjugated dienes is shown in invention runs 10, 13, 16, 17 and 18 andsuch other physical properties as flexural strength, elongation, glossand surface roughness (when determined) are also considered to besatisfactory. Invention run 13 shows that the carboxy-terminatedpolymers can be admixed with up to about 50 weight percent of anon-carboxy rubber, such as a linear block copolymer or a radial blockcopolymer and still obtain compositions exhibiting a good balance ofphysical properties. The relatively good reverse impact of control run11 represents an anomalous result but in any event the gloss is poor.Admixing a linear block (i.e. ABA) polymer with a linear AB blockpolymer as in the run 12 composition gives a reverse impact value aboutthe same as in the other control runs. Control runs 14 and 15 show thatwhile good reverse impact can be obtained with low molecular weightcarboxy terminated polymer, the compositions are unsatisfactory becauseof high surface roughness. Invention run 16 has a reverse impactstrength of 7 at a low loading of calcium carbonate. At the same lowloading of calcium carbonate a control run made without the normallysolid carboxy-containing polymer of a conjugated diene had a reverseimpact strength of 3.5 inches.

A visual examination of the molded plaques of the invention showeduniform pigmentation compared with a mottled appearance of the sampleusing the commercial polyvinyl acetate modifier (run 3).

While this invention has been described in detail for the purpose ofillustration it is not to be construed as limited thereby but isintended to cover all changes and modifications within the spirit andscope thereof.

What is claimed is:
 1. A .Iadd.cured thermoset article produced bysubjecting to heat a thermosetting .Iaddend.composition comprising:a. anunsaturated polyester prepared by reacting an unsaturated dicarboxylicacid and a polyol; b. .Iadd.a diene component consisting essentially of.Iaddend.a normally solid carboxy-containing polymer of a conjugateddiene having a weight average molecular weight within the range of.[.30,000.]. .Iadd.50,000 .Iaddend.to .[.400,000.]. .Iadd.250,000 andwherein said carboxy-containing polymer has a polymerized conjugateddiene content of from 55 to 100 weight percent.Iaddend.; c. a vinylmonomer; d. a catalyst; and e. .[.at least one of.]. a .Iadd.fibrous.Iaddend.reinforcing agent .[.or a filler.]..
 2. .[.A composition.]..Iadd.An article .Iaddend.according to claim 1 wherein said polymer of aconjugated diene has .[.a weight average molecular weight within therange of 50,000 to 250,000 and.]. an inherent viscosity within the rangeof 0.6 to
 2. 3. .[.A composition.]. .Iadd.An article .Iaddend.accordingto claim 1 wherein said polymer of a conjugated diene is a copolymer ofbutadiene and styrene.
 4. .[.A composition.]. .Iadd.An article.Iaddend.according to claim 1 wherein said polyester is prepared byreacting fumaric acid and propylene glycol.
 5. .[.A composition.]..Iadd.An article .Iaddend.according to claim 1 wherein said vinylmonomer is styrene.
 6. .[.A composition.]. .Iadd.An article.Iaddend.according to claim 1 wherein a ratio of (a) to (b) is withinthe range of 5:1 to 1:1 and wherein said vinyl monomer is present in anamount within the range of 30 to 200 parts by weight per 100 parts byweight of (a) plus (b).
 7. .[.A composition.]. .Iadd.An article.Iaddend.according to claim 1 wherein said catalyst is a peroxide.Iadd.and said composition contains in addition a lubricant and athickener. .Iaddend.
 8. .[.A composition.]. .Iadd.An article.Iaddend.according to claim 1 .[.containing.]. .Iadd.wherein saidfibrous reinforcing agent is composed of .Iaddend.glass fibers and.Iadd.wherein said composition contains in addition .Iaddend.calciumcarbonate.
 9. .[.A composition.]. .Iadd.An article .Iaddend.according toclaim 1 wherein said unsaturated polyester is produced by reactingfumaric acid and propylene glycol, said normally solidcarboxy-containing polymer is a copolymer of butadiene and styrenecharacterized by a vinyl addition of 5 to 76 percent and having 0.01 to5 weight percent carboxyl content, said vinyl monomer is styrene, aratio of (a) to (b) being within the range of 5:1 to 1:1, said vinylmonomer is present in an amount within the range of 30 to 200 parts byweight per 100 parts by weight of (a) plus (b), said catalyst istertiary butyl perbenzoate present in an amount within the range of 1-5parts by weight per 100 parts by weight of (a) plus (b).Iadd., saidfibrous reinforcing agent is composed of glass fibers present in anamount within the range of 40 to 200 parts by weight per 100 parts byweight of (a) plus (b) .Iaddend.and wherein said composition containscalcium carbonate filler in an amount within the range of 200 to 800parts by weight of filler per 100 parts .[.per.]. .Iadd.by.Iaddend.weight of (a) plus (b), .[.glass fiber reinforcing agent in anamount within the range of 40 to 200 parts by weight per 100 parts byweight of (a) plus (b),.]. 1 to 15 parts by weight of zinc stearate per100 parts by weight of (a) plus (b) and 1 to 10 parts by weight ofmagnesium hydroxide per 100 parts by weight of (a) plus (b). .[.10. Acured article produced by subjecting the composition of claim 9 toheat..]. .[.11. A cured article produced by subjecting the compositionof claim 1 to heat..].
 12. A method of forming thermosettingcompositions suitable for preparing reinforced plastic articlescomprising milling together under conditions of moderate shear:a. anunsaturated polyester prepared by reacting an unsaturated dicarboxylicacid and a polyol; b. a normally solid carboxy-containing polymer of aconjugated diene having a weight average molecular weight within therange of 30,000 to 400,000; c. a vinyl monomer; d. a catalyst; and e..[.at least one of.]. a .Iadd.fibrous .Iaddend.reinforcing agent .[.or afiller.]..
 13. A method according to claim 12 wherein said milling isdone with a twin-rotor mixer using sigma blades.
 14. A method accordingto claim 13 wherein said unsaturated polyester is produced by reactingfumaric acid and propylene glycol, said normally solidcarboxy-containing polymer is a copolymer of butadiene and styrenecharacterized by a vinyl unsaturation of 5 to 76 percent and having 0.01to 5 weight percent carboxyl content, said vinyl monomer is styrene, aratio of (a) to (b) is within the range of 5:1 to 1:1, said vinylmonomer is present in an amount within the range of 30 to 200 parts byweight per .[.110.]. .Iadd.100 .Iaddend.parts by weight of (a) plus (b),said catalyst is tertiary butyl perbenzoate.Iadd., said fibrousreinforcing agent is composed of glass fibers present in an amountwithin the range of 40 to 200 parts by weight per 100 parts by weight of(a) plus (b) .Iaddend.and wherein said composition contains calciumcarbonate filler in an amount within the range of 200 to 800 parts byweight of filler per 100 parts .[.per.]. .Iadd.by .Iaddend.weight of (a)plus (b), .[.glass fiber reinforcing agent in an amount within the rangeof 40 to 200 parts by weight of (a) plus (b),.]. 1 to 15 parts by weightof a lubricant per 100 parts by weight of (a) plus (b) and 1 to 10 partsby weight of an oxide or hydroxide of a group II metal.
 15. A methodaccording to claim 13 wherein said shear produces a temperature rise of2° to 30° C.
 16. A method according to claim 12 wherein the resultingcomposition is subjected to curing conditions of 100° C. to 200° C. fora time within the range of 1 to 15 minutes. .Iadd.
 17. A compositionconsisting essentially of:a. an unsaturated polyester prepared byreacting an unsaturated dicarboxylic acid and a polyol; b. a normallysolid carboxy-containing polymer of a conjugated diene having a weightaverage molecular weight within the range of 30,000 to 400,000 andwherein said carboxy-containing polymer has a polymerized conjugateddiene content of from 55 to 100 weight percent; c. a vinyl monomer; d. acatalyst; e. a fibrous reinforcing agent; f. a lubricant selected fromaluminum stearate, barium stearate, clacium stearate, magnesium stearateof zinc stearate; g. a thickener selected from oxides and hydroxides ofmagnesium, calcium, strontium, barium and zinc; and h. a filler..Iaddend. .Iadd.
 18. A composition according to claim 17 wherein saidunsaturated polyester is prepared by reacting fumaric acid and propyleneglycol, said normally solid carboxy-containing polymer is a copolymer ofbutadiene and styrene characterized by a vinyl unsaturation of 5 to 76percent and having 0.01 to 5 weight percent carboxyl content, said vinylmonomer is styrene, a ratio of (a) to (b) is within the range of 5:1 to1:1, said vinyl monomer is present in an amount within the range of 30to 200 parts by weight per 100 parts by weight of (a) plus (b), saidcatalyst is tertiary butyl perbenzoate present in an amount within therange of 1-5 parts by weight per 100 parts by weight of (a) plus (b),said fibrous reinforcing agent is composed of glass fibers present in anamount within the range of 40 to 200 parts by weight per 100 parts byweight of (a) plus (b), said lubricant is zinc stearate present in anamount within the range of 1-15 parts by weight per 100 parts by weightof (a) plus (b), said thickener is magnesium hydroxide present in anamount within the range of 1-10 parts by weight per 100 parts by weightof (a) plus (b) and said filler is calcium carbonate present in anamount within the range of 200 to 800 parts by weight per 100 parts byweight of (a) plus (b). .Iaddend.